Hi, Daniel
On 2022/12/6 4:05, Daniel Borkmann wrote:
> On 12/5/22 9:13 AM, Miaoqian Lin wrote:
>> strdup() allocates memory for path. We need to release the memory in
>> the following error paths. Add free() to avoid memory leak.
>>
>> Fixes: 8f184732b60b ("bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects")
>> Signed-off-by: Miaoqian Lin <linmq006@xxxxxxxxx>
>> ---
>> tools/bpf/bpftool/common.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
>> index 0cdb4f711510..8a820356525e 100644
>> --- a/tools/bpf/bpftool/common.c
>> +++ b/tools/bpf/bpftool/common.c
>> @@ -499,9 +499,11 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb,
>> if (err) {
>> p_err("failed to append entry to hashmap for ID %u, path '%s': %s",
>> pinned_info.id, path, strerror(errno));
>> - goto out_close;
>> + goto out_free;
>> }
>> +out_free:
>> + free(path);
>
> It would be ok if you were to add the free(path) into the err condition, but here you
> also cause the !err to be freed which would trigger as UAF. See the hashmap_insert()
> where just set the pointer entry->value = <path>.. how was this tested before submission?
>
Thanks for your review. You're right. Sorry for the mistake, I meant to free it in the error path.
I'll send v2 to fix this. I spotted it with static detection tool.
>> out_close:
>> close(fd);
>> out_ret:
>>
>
